Originally Posted by
Vernon Demerest
The CAL 757-200s had max takeoff of 255,000lbs which was artificially reduced to 250,000 at some point vs the 240,000 of the older model 757s with the Pratt motors. Only flew the RR powered birds so cannot speak to the engine specifics. Anything seemingly “better” would probably be the newer airframe with ETOPS certification (specific to engine and airframe combo) and higher max gross takeoff weight (which was needed for trans-Atlantic max tank capacity flights).
The legacy UAL Pratt 757’s were 232,000 lbs originally as I recall. They then got the upgrade to 240,000. But remember UAL had no need for the 757’s to cross the Atlantic, we had the 767-200 and then the 767-300 for that mission. Domestic and Hawaii Etops were the mission.
If the thrust of the Pratt and the Rolls are the same (or similar) then the Pratt’s should be capable of the 255,000 weight as well. Checking the flight manuals, the PW UAL 757’s has the low thrust version of 37,000 (but PW does make a version that can produce 43,700).
So put a newer Pratt 2000 engine on a legacy UAL 757 and it will lift the 255,000.